- Pp. 178-207 (30)Sara Correia Santos, Manuela Oliveira and Teresa Semedo Lemsaddek
Bacteriocins are antimicrobial peptides produced by numerous bacteria, which may present narrow or broad host range. These ribosomally synthesized antimicrobial peptides are considered a successful strategy in maintaining equilibrium within a bacterial ecosystem. These compounds kill other bacteria by several mechanisms, including the modification of membrane permeability and depolarization of membrane ion gradients, the degradation of nucleic acids or cell walls. In literature, the term bacteriocin is usually restricted to peptides produced by Gram-positive bacteria, while in Gram-negative bacteria, mainly enterobacteria, the toxins are called either colicins (i.e. antibiotic proteins targeting Escherichia coli) or microcins. Many bacteriocins are produced by food-grade lactic acid bacteria, a phenomenon which offers the possibility for preventing the development of specific bacterial species in food. This can be particularly useful in preservation or food safety applications, but also has implications for the development of desirable flora in fermented food. In this sense, bacteriocins can be used to confer a protection and at the same time help processors extend shelf-life after product manufacture.